The aim of this study was to determine the effectiveness of physical exercise, respiratory muscle training, and the self-management World Health Organization (WHO) recommendations leaflet on the recovery of physical fitness, quality of life, and symptom status in people with post-COVID-19 conditions. Eighty nonhospitalized adults with a post-COVID-19 condition were randomly assigned to one of four 8-wk parallel intervention groups: 1) multicomponent exercise program based on concurrent training (CT, number of subjects (n) = 20; 3 resistance and endurance supervised sessions per week at low-moderate intensity); 2) inspiratory muscle training (RM, n = 17; 2 standardized daily sessions); 3) a combination of both of the above (CTRM, n = 23); and 4) control group (CON, n = 20; following the WHO guidelines for post-COVID-19-related illness rehabilitation). No significant differences between groups were detected at baseline. Although no significant differences between interventions were detected in the V̇o2max, significant individual improvements were identified in the CT (7.5%; effect size, ES = 0.28) and CTRM (7.8%; ES = 0.36) groups. Lower body muscle strength significantly improved in the CT and CTRM (14.5%-32.6%; ES = 0.27-1.13) groups compared with RM and CON (-0.3% to 11.3%; ES = 0.10-0.19). The CT and CTRM groups improved significantly for dyspnea and fatigue, as did the health status. In addition, significant differences between interventions were described in fatigue and depression scales favoring CT and CTRM interventions. An individualized and supervised concurrent training with or without inspiratory muscle training was safe and more effective than self-care recommendations and inspiratory muscle training alone, to regain cardiovascular and muscular fitness, improve symptom severity, and health status in outpatients with post-COVID-19 conditions.NEW & NOTEWORTHY Eight weeks of concurrent training, with or without inspiratory muscle exercise, was better than WHO "Support for Rehabilitation: Self-Management after COVID-19-Related Illness" recommendations or inspiratory muscle training alone to improve cardiopulmonary fitness, strength, and symptom severity, in a safe and effective manner. The RECOVE trial proved the benefits and utility of a supervised exercise program in people with post-COVID-19 conditions after mild COVID-19 in an ambulatory setting.
Keywords: fatigue; long COVID; physical activity; post-COVID-19 syndrome; quality of life.